constify security_sb_mount()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 912deee..e3aeacc 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2760,7 +2760,7 @@
 }
 
 static int selinux_mount(const char *dev_name,
-			 struct path *path,
+			 const struct path *path,
 			 const char *type,
 			 unsigned long flags,
 			 void *data)